Dyeing is a process of adding colorant molecules to textiles and then permanently holding these molecules inside the fabrics under certain kinds of washing conditions. Using this process, the desired colors can be generated (see, J. Marshall, Physical Chemistry Essential to Dyeing Theory, in The Theory of Coloration of Textiles, “Ed. C. L. Bird and W. S. Boston” (SDC, Bradford, 1975); H. Zollinger, Color Chemistry (VCH, Weinheim, 1991); P. R. Brady, Rev. Prog. Coloration, 22:58 (1992)). To fulfill the dyeing purpose, it is preferable that the colorant molecules be both soluble in water and interact with the textile's polymeric molecules. Dissolution of colorants consumes huge amounts of water and then the same volume of wastewater is produced after the dyeing operation (see, S. Papic et al, J. S. D. C., 116(11):52 (2000); V. V. Konovalova et al, Bioprocess Engineering, 23(6):52 (2000); J. Sarasa et al, Water Research, 32(9):721 (1998); P. Cooper, J. S. D. C., 109:7 (1993)). The colored wastewater is treated before being discarded into the environment, which adds even more costs to the products. In addition, the variety of fiber forming polymer structures requires a comparable large number of colorant molecules to interact, and thus generate the proper colors with the desired durability in the fibers. The selection of both the dyes and the dyeing conditions is therefore complicated and varies from one fabric to another. The problem of multiplicity of dyeing, becomes even more serious in the case of dyeing blended fabrics with a solid color effect, as the dyeing operation has to proceed in multiple steps with different dyes of the same exact color being employed in each step of the coloration process (see, J. Shore, Dyeing of Blends, in The dyeing of Synthetic-Polymer and Acetate Fibers, “Ed. D. M. Nunn (The Dyers Company Publications Trust, Bradford, SDC” p. 409 (1979)).
Pigments, another group of colorants, can be categorized as being either organic or inorganic, and are regarded as being both insoluble in water and having no interactions with polymeric textiles (see, H. Zollinger, Color Chemistry (VCH, Weinheim, 1991); W. Herbst et al., Industrial Organic Pigments (VCH, Weinheim, 1993); G. Buxbaum, Industrial Inorganic Pigments (Wiley-VCH, Weinheim, 1998)). Pigments, especially inorganic pigments, have been widely used in applications including coatings, printings, and paintings. When pigments are used for the coloration of textiles, various processes are employed including pigment padding, batch exhaustion, and pigment printing. These processes sometimes include binders, solvents, and other optional additives (see, W. Herbst et al., Industrial Organic Pigments (VCH, Weinheim, 1993); G. Buxbaum, Industrial Inorganic Pigments (Wiley-VCH, Weinheim, 1998); S. R. Khanna, Colourage, 39(3):13 (1992); J. R. Aspland, Textile Chem. Color., 25(10):31 (1993); A. H. Tabba et al., Textile Chem. Color. & American Dyestuff Reporter, 32(2):30 (2000); W. Schwindt et al., Rev. Prog. Coloration, 14:166 (1984)). Using these techniques, the coloration occurs at the surface of the fabrics between the textile polymers and the pigment molecules, wherein mechanistically, the binders serve as a bridge. This particular mechanism adds limitations to this method of coloration.
More recently, pigment dyeing has been developed and applied to cotton coloration (see, T. Lever, J. S. D. C., 108:477 (1992)). It is actually not really “dyeing” in a true sense, but the garments colored this way can produce a unique and fashionable “washed-down” or “ready-worn” look similar to that of the stone-wash effect popular on denim wear. Synthetic fibers however, seem more difficult to be colored through pigment dyeing.
The traditional dyeing technique in which water serves as the medium for carrying dyes to polymeric textiles produces a great volume of colored and/or toxic wastewater and costs millions of dollars for treatment (see, H. Zollinger, Color Chemistry (VCH, Weinheim, 1991); A. Reife et al., Textile Chem. Color. & American Dyestuff Reporter, 32(1):56 (2000); Q, Zhou, Bull. Envion. Contam. Toxicol. 66(6):784 (2001); W. Herbst et al., Industrial Organic Pigments (VCH, Weinheim, 1993); G. Buxbaum, Industrial Inorganic Pigments (Wiley-VCH, Weinheim, 1998)). New technologies with different mechanisms of coloration are certainly needed.
Nanoparticles are used in materials such as dispersions and coatings, which are used to make films and paints. A major use of bulk nanoparticles is in high surface area materials. These include catalysts, porous membranes, molecular scale filters, sieves such as zeolites, materials used in combustion processes such as rocket fuels, and other applications such as energy storage and sensors. However, nanoparticles have not been used in the dyeing of textiles.
In view of the foregoing, new colored textiles as well as innovative dyeing methods are needed having good fastness without the environmental liabilities. The present invention satisfies these and other needs.